Determination of discharge point of cathodic protection

For the buried metal structures under the influence of AC interference, one or several drainage protection measures can be adopted according to the actual situation. Based on the investigation and test results, one or more points on the disturbed structure should be selected as the drainage points, and the drainage protection measures should be set at these drainage points. The selection of discharge point should be based on the best protection effect. The discharge point should be determined by field simulation test. For buried metal pipeline, it can be determined according to the following conditions.

1、 Mutual location conditions:

1. The first and the last two ends of the disturbed pipeline;

2. The pipeline approaches or leaves the "public corridor" and has a parallel section with the interference source;

3. Sudden change of distance between pipeline and interference source;

4. The minimum distance between pipeline and interference source;

5. The pipeline passes through the interference source.


2、 Technical conditions:

1. The most positive position of pipe ground potential;

2. The pipe ground potential is positive and the duration is longer;

3. Transposition of high voltage transmission line conductor;

4. The parts where the resistivity and earth conductivity of pipeline anti-corrosion coating change;

5. The place with small soil resistivity and convenient ground bed setting.


3、 The technical requirements for the drainage device shall meet the following conditions:

1. It can work reliably within the range of AC interference voltage amplitude;

2. It can follow the sharp change of pipe ground potential in time;

3. Overload protection capability;

4. Simple structure, easy installation, adapt to the field environment, easy to maintain;

5. The rated current of drain and drain line is 1.5 ~ 2 times of the calculated discharge.

Shandong Linyi Bosi conductive materials Co., Ltd. is a high-tech enterprise specializing in the production of MMO flexible anode, conductive polymer flexible anode and titanium coated anode, mainly providing cathodic protection technology, engineering design, installation and technical services. 

Tel: +86 17568010262，0539-3712117.